Heckler & Koch HK416

The Heckler & Koch HK416 is an assault rifle designed and manufactured by Heckler & Koch. It is an improved version of the M4 carbine with many changes, most notably a new gas operating system from the G36.

The US Army's Delta Force collaborated with the German arms maker to develop the new carbine. Delta replaced its M4s with the HK416 in 2004 after tests revealed that the piston operating system significantly reduces malfunctions while increasing the life of parts.

The project was originally called the HK M4, but this was changed in response to a trademark infringement suit filed by Colt Defense. The weapon has been tested by the United States military and is in use with some law enforcement agencies and special operations units. It has been adopted as the standard rifle in two NATO nations as well.

HK416
Type	Assault Rifle
Place of origin	Germany United States
Service history
In service	2005–present
Used by	See Users
Wars	Iraq War, War in Afghanistan
Production history
Designer	Ernst Mauch
Manufacturer	Heckler & Koch
Produced	2005–present
Variants	D10RS, D14.5RS, D16.5RS, D20RS, MR223, HK417
Specifications
Weight	D10RS: 3.02 kg (6.7 lb) D14.5RS: 3.490 kg (7.69 lb) D16.5RS: 3.560 kg (7.85 lb) D20RS: 3.855 kg (8.50 lb)
Length	D10RS: 797 mm (31.4 in) stock extended / 701 mm (27.6 in) stock collapsed D14.5RS: 900 mm (35.4 in) stock extended / 804 mm (31.7 in) stock collapsed D16.5RS: 951 mm (37.4 in) stock extended / 855 mm (33.7 in) stock collapsed D20RS: 1,037 mm (40.8 in) stock extended / 941 mm (37.0 in) stock collapsed
Barrel length	D10RS: 264 mm (10.4 in) D14.5RS: 368 mm (14.5 in) D16.5RS: 419 mm (16.5 in) D20RS: 505 mm (19.9 in)
Width	78 mm (3.1 in)
Height	240 mm (9.4 in)
Cartridge	5.56x45mm NATO
Action	Gas-operated, rotating bolt
Rate of fire	850 rounds/min (cyclic)
Muzzle velocity	Varies by barrel length and type of round used.
Feed system	20, 30-round STANAG magazine or 100-round Beta C-Mag
Sights	Rear rotary diopter sight and front post, Picatinny rail

The Heckler & Koch HK416 uses a proprietary gas system derived from the HK G36, replacing the direct impingement gas system used by the standard M16/M4. The HK system uses a short-stroke piston driving an operating rod to force the bolt carrier to the rear. This design prevents combustion gases from entering the weapon’s interior, a shortcoming with direct impingement systems. The reduction in heat and fouling of the bolt carrier group increases the reliability of the weapon and extends the interval between stoppages. It also reduces operator cleaning time and stress on critical components.

The Heckler & Koch HK416 is equipped with a proprietary accessory rail forearm with MIL-STD-1913 rails on all four sides. This allows most current accessories, used on M4/M16-type weapons, to be fitted to the HK416. The HK416 rail forearm can be installed and removed without tools by using a bolt locking lug as the screwdriver. The rail forearm is of the 'free-float' variety; it does not contact the barrel and improves accuracy.

The Heckler & Koch HK416 barrel is cold hammer-forged with a 20,000 round service life. The cold hammer-forging process provides a stronger barrel for greater safety in case of an obstructed bore or for extended firing sessions. This includes "OTB" (Over-the-beach) capability; the HK416 can be safely fired after being submerged in water and not completely drained.